From the Guidelines
Shingles affecting the frontotemporal nerve can potentially lead to blindness if it involves the eye, a condition called herpes zoster ophthalmicus, and prompt treatment with antiviral medications is crucial to reduce the risk of eye complications. When shingles affects this nerve and spreads to the eye, it can cause serious complications including corneal scarring, inflammation inside the eye, increased eye pressure, and damage to the retina or optic nerve, as noted in the study on conjunctivitis preferred practice pattern 1. These complications, if not promptly and properly treated, can result in permanent vision loss or blindness.
The most effective strategy to prevent varicella, HZ, and its related complications, including blindness, is by vaccination, as recommended in the study on recommendations and guidance for herpes zoster vaccination for adults in Taiwan 1. Early treatment with antiviral medications like acyclovir (800 mg five times daily for 7-10 days), valacyclovir (1000 mg three times daily for 7 days), or famciclovir (500 mg three times daily for 7 days) is crucial to reduce the risk of eye complications, as suggested in the study on conjunctivitis preferred practice pattern 1.
Key considerations in managing shingles affecting the frontotemporal nerve include:
- Prompt recognition of the condition and its potential to cause serious eye complications
- Early initiation of antiviral therapy to reduce the risk of complications
- Monitoring for signs of eye involvement, such as eye pain, redness, or vision changes
- Aggressive treatment in immunocompromised individuals or those with impaired renal clearance, as cautioned in the study on conjunctivitis preferred practice pattern 1
- Consideration of prolonged treatment or long-term prophylaxis in patients with chronic sequelae, as noted in the study on conjunctivitis preferred practice pattern 1.
From the Research
Shingles and Blindness
- Shingles of the frontotemporal nerve, also known as herpes zoster ophthalmicus, can lead to blindness due to the potential for ocular involvement and complications such as conjunctivitis, keratitis, uveitis, and optic neuropathy 2, 3.
- The ophthalmic division of the trigeminal nerve is affected in herpes zoster ophthalmicus, which can result in permanent sequelae including chronic ocular inflammation, loss of vision, and debilitating pain 2.
- Antiviral medications such as acyclovir, valacyclovir, and famcidovir are effective in preventing ocular involvement when begun within 72 hours after the onset of the rash 2.
- Timely diagnosis and management of herpes zoster ophthalmicus, with referral to an ophthalmologist when ophthalmic involvement is present, are critical in limiting visual morbidity 2, 3.
Ocular Complications
- Ocular disease occurs in approximately 50% of patients with herpes zoster ophthalmicus, and up to 25% of these patients develop chronic or recurrent disease 3.
- Common manifestations of ocular disease include conjunctivitis, keratitis, and uveitis, whereas optic neuropathy and retinitis are uncommon 3.
- Extraocular muscle palsies can occur, with the third nerve being the most commonly affected and the fourth nerve the least 4.
- Combined involvement of the optic nerve and isolated paralysis of the eye muscle is very rare, but can occur in some cases of herpes zoster ophthalmicus 4.
Prevention and Treatment
- Herpes zoster ophthalmicus is preventable by vaccination against herpes zoster, with both the recombinant adjuvanted vaccine (RZV) and live-attenuated vaccine (ZVL) significantly reducing the incidence of herpes zoster and herpes zoster ophthalmicus in older adults 3.
- Early recognition and timely treatment with antivirals may prevent ocular complications, and corticosteroids may be used to treat optic nerve involvement and extraocular muscle palsies 3, 4.